1. Field of the Invention
This invention relates generally to systems for drilling boreholes for the production of hydrocarbons and more particularly to an automated rig control management system having a hiearchical and authenticating communication interface to the various service contractor and rig operation inputs and using a control model for allocating and regulating rig resources according to operating rules programmed into the control management system to achieve the desired well plan within the operational constraints of the drilling rig equipment and borehole.
2. Description of the Related Art
To obtain hydrocarbons such as oil and gas, boreholes are drilled by rotating a drill bit attached at a drill string end. A large proportion of the current drilling activity involves directional drilling, i.e., drilling deviated and horizontal boreholes, to increase the hydrocarbon production and/or to withdraw additional hydrocarbons from the earth's formations. Modern directional drilling systems generally employ a drill string having a bottomhole assembly (BHA) and a drill bit at end thereof that is rotated by a drill motor (mud motor) and/or the drill string. A number of downhole devices placed in close proximity to the drill bit measure certain downhole operating parameters associated with the drill string. Such devices typically include sensors for measuring downhole temperature and pressure, azimuth and inclination measuring devices and a resistivity-measuring device to determine the presence of hydrocarbons and water. Additional downhole instruments, known as logging-while-drilling (“LWD”) and/or measurement-while drilling (“MWD”) tools, are frequently attached to the drill string to determine the formation geology and formation fluid conditions during the drilling operations.
Pressurized drilling fluid (commonly known as the “mud” or “drilling mud”) is pumped into the drill pipe to rotate the drill motor and to provide lubrication to various members of the drill string including the drill bit. The drill pipe is rotated by a prime mover, such as a motor, to facilitate directional drilling and to drill vertical boreholes.
Boreholes are usually drilled along predetermined paths and the drilling of a typical borehole proceeds through various formations. The drilling operator typically controls the surface-controlled drilling parameters, such as the weight on bit, drilling fluid flow through the drill pipe, the drill string rotational speed (rpm of the surface motor coupled to the drill pipe) and the density and viscosity of the drilling fluid to optimize the drilling operations. The downhole operating conditions continually change and the operator must react to such changes and adjust the surface-controlled parameters to optimize the drilling operations. For drilling a borehole in a virgin region, the operator typically has seismic survey plots that provide a macro picture of the subsurface formations and a pre-planned borehole path. For drilling multiple boreholes in the same formation, the operator also has information about the previously drilled boreholes in the same formation. Additionally, various downhole sensors and associated electronic circuitry deployed in the BHA continually provide information to the operator about certain downhole operating conditions, condition of various elements of the drill string and information about the formation through which the borehole is being drilled.
Typically, the information provided to the operator during drilling includes drilling parameters, such as WOB, rotational speed of the drill bit and/or the drill string, and the drilling fluid flow rate. In some cases, the drilling operator is also provided selected information about bit location and direction of travel, bottomhole assembly parameters such as downhole weight on bit and downhole pressure., and possibly formation parameters such as resistivity and porosity.
Typically, regardless of the type of the borehole being drilled, the operator continually reacts to the specific borehole parameters and performs drilling operations based on such information and the information about other downhole operating parameters, such as bit location, downhole weight on bit and downhole pressure, and formation parameters, to make decisions about the operator-controlled parameters. Thus, the operators base their drilling decisions upon the above-noted information and experience. Drilling boreholes in a virgin region requires greater preparation and understanding of the expected subsurface formations compared to a region where many boreholes have been successfully drilled. The drilling efficiency can be greatly improved if the operator can simulate the drilling activities for various types of formations. Additionally, further drilling efficiency can be gained by simulating the drilling behavior of the specific borehole to be drilled by the operator.
Commonly, the LWD and MWD tools and sensors are owned and operated by a service contractor. The service contractor makes recommendations from the processed downhole data for adjusting rig operating parameters to achieve desired well plan objectives. Similarly, other service contractors may be providing information concerning the drilling fluids and solids control. Yet another service contractor may be providing underbalanced drilling services. All of these service contractors commonly provide their own separate recommendations regarding the adjustment of various operating parameters to effect a desired change to achieve desired well plan objectives. However, these recommendations must be reviewed by the rig operator to insure that the drilling rig has the capability to execute the recommendations in a safe and efficient manner. Further, these recommendations must be reviewed by other rig personnel, such as the oil company representative, to insure that they are consistent and that they will not adversely impact other aspects of the borehole. For example, it may be desirable to increase the circulating rate of the drilling mud to improve removal of cuttings from the bottom of the borehole. However, this action may cause internal pressures of the borehole to rise above desirable limits resulting in a degradation of the producing capability of the borehole once drilling is completed.
Currently, these recommendations are reconciled through structured or ad hoc meetings among the service contractors, rig operator, and company representative at the rig site. The results of these meetings are communicated to the rig operator to execute. This process is prone to error. For example, instructions may be misinterpreted by the rig operator, or misinterpreted by the drilling crew to which they are communicated, and executed improperly. Or, the instructions may not be passed on correctly to subsequent drilling crews on subsequent work shifts. Or, during the evaluation of the various recommendations, important constraints regarding the capabilities of the rig equipment, or aspects of the well plan such as borehole quality and integrity, or subtle but important incompatibilities among the recommendations, may be overlooked or ignored. Even when such recommendations are successfully resolved and communicated properly to the rig operator, it is still an inefficient process, which wastes potentially productive time in meetings and getting necessary authorizations.
A few systems have been proposed for automated operation of portions of a drilling operation. For example, U.S. Pat. Nos. 6,233,524 and 5,842,149 describe “closed loop” drilling systems in which a number of drilling-related parameters are detected. Thereafter, the system either adjusts automatically based upon these sensed conditions, or prompts an operator to make an adjustment. However, these systems do not provide any mechanism for accommodating more than one person to control various aspects of the drilling operation.
As the “closed loop” systems described illustrate, there is a trend toward greater automation in the drilling process in which multiple parameters that were once controlled manually by a single drilling operator may now be regulated automatically by a computer, albeit with human assistance for programming control parameters and the like of the computer equipment. Despite these advances, though, the location where the control parameters are entered and monitored remains the floor of the drilling rig, and, as a result the driller remains the default operator. As noted above, this arrangement becomes problematic as drilling processes advance in complexity. As noted above, decisions regarding the ideal settings for control parameters are increasingly not made by the driller, and current methods for funneling the needed information to the driller are fraught with difficulties. In fact, mud logging companies, bit companies, and off-site operating company personnel with access to formation and survey data all have the potential to set and alter these drilling parameters to the benefit of the drilling process. Systems are needed that will permit effective and structured use of such drilling equipment.
Thus, there is a need for a system that overcomes the problems associated with the prior art systems.